Hybrid Teas and Grandifloras. By winter, hybrid tea roses and grandifloras are generally 8 to 10 feet tall and looking rather lanky. You can prune these canes (on an established bush) 2 to 4 feet but, in general, leave 4 to 5 major canes with an average height of 3 feet. Remove the older canes; it will trigger the rose bush to attempt basal breaks (new cane growth) in the spring. This regenerative process is fundamental to the health of the bush.
Floribundas and Polyanthas. Since floribundas and polyanthas are mainly for garden display rather than cut flowers, you can allow more older canes to remain for increased flower production. Cut back about one third of the year's new growth and leave substantially more stems than you would for a hybrid tea. By nature, floribundas and polyanthas produce large numbers of flowers. Leaving a greater number of canes enhances the ability of the rose bush to produce the maximum number of flowers.
Miniature Roses. Most miniature roses are grown on their own roots. There is no bud union and no suckers. Precise pruning of miniature roses is very labor intensive, and many rosarians simply use a hedge clipper to trim off the tops at a foot above the soil (height varies with the variety). After such treatment, remove any twiggy growth and open up the center of the plant to increase air circulation.
Old Garden Roses and Shrubs. When pruning old garden roses, don't treat them as modern hybrid teas or floribundas. For maximum blooms, pruning should be more of a light grooming than severe. Prune only last year's growth; prune one-time bloomers immediately after flowering; prune one-time bloomers immediately after flowering; prune repeat bloomers in winter or early spring. After a few years, however, this practice makes for a very lanky bush, so each year thereafter prune back some of the oldest canes to promote basal and post-basal breaks. Keeping a proper balance between new growth and continuing old growth patterns is the secret to growing old garden roses.
Climbers and Ramblers. Climbers will generally not flower profusely unless the canes are trained on a horizontal plane. Cut the long-established canes to about the place where they are slightly thicker than a pencil. Then, cut each side stem that has flowered to the lowest possible five-leaflet stem, about 1 to 2 inches from the main cane. This process will cause the cane to flower along its complete length for a spectacular spring display.